Light-sensitive material containing silver halide, reducing agent and polymerizable compound wherein the light-sensitive layer is provided with a cover sheet

ABSTRACT

A light-sensitive material comprising a light-sensitive layer which contains silver halide, a reducing agent and a polymerizable compound and support, wherin the light-sensitive layer is provided thereon with a cover sheet. A light-sensitive material comprising the light-sensitive layer and a support, wherein the light-sensitive layer is provided thereon with a protective layer is also disclosed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a light-sensitive material comprising alight-sensitive layer containing silver halide, a reducing agent and apolymerizable compound provided on a support, and image-forming methodsemploying the light-sensitive material.

2. Description of the Prior Arts

Light-sensitive materials comprising a light-sensitive layer containingsilver halide, a reducing agent and a polymerizable compound provided ona support can be used in an image forming method in which a latent imageof silver halide is formed, and then the polymerizable compound ispolymerized to form the corresponding image.

Examples of said image forming methods are described in Japanese PatentPublication Nos. 45(1970)-11149 (corresponding to U.S. Pat. No.3,697,275), 47(1972)-20741 (corresponding to U.S. Pat. No. 3,687,667)and 49(1974)-10697, and Japanese Patent Provisional Publication Nos.57(1982)-138632, 57(1982)-142638, 57(1982)-176033, 57(1982)-211146(corresponding to U.S. Pat. No. 4,557,997), 58(1983)-107529(corresponding to U.S. Pat. No. 4,560,637), 58(1983)-121031(corresponding to U.S. Pat. No. 4,547,450) and 58(1983)-169143. In theseimage forming methods, when the exposed silver halide is developed usinga developing solution, the polymerizable compound is induced topolymerize in the presence of a reducing agent (which is oxidized) toform a polymer image. Thus, these methods need a wet development processemploying a developing solution. Therefore the process takes arelatively long time for the operation.

An improved image forming method employing a dry process is described inJapanese Patent Provisional Publication Nos. 61(1986)-69062 and61(1986)-73145 (the contents of both publications are described in U.S.Pat. No. 4,629,676 and European Patent Provisional Publication No.0174634A2). In this image forming method, a recording material (i.e.,light-sensitive material) comprising a light-sensitive layer containinga light-sensitive silver salt (i.e., silver halide), a reducing agent, across-linkable compound (i.e., polymerizable compound) and a binderprovided on a support is imagewise exposed to form a latent image, andthen the material is heated to polymerize within the area where thelatent image of the silver halide has been formed. The above methodemploying the dry process and the light-sensitive material employablefor such method are also described in Japanese Patent ProvisionalPublication Nos. 61(1986)-183640, 61(1986)-188535 and 61(1986)-228441.

The above-mentioned image forming methods are based on the principle inwhich the polymerizable compound is polymerized in the portion where alatent image of the silver halide has been formed.

Japanese Patent Provisional Publication No. 61(1986)-260241(corresponding to U.S. Pat. Ser. No. 854,640) describes another imageforming method in which the polymerizable compound in a portion where alatent image of the silver halide has not been formed is polymerized. Inthis method, when the material is heated, the reducing agent functionsas polymerization inhibitor in the portion where a latent image of thesilver halide has been formed, and the polymerizable compound in theother portion is polymerized.

The light-sensitive material employed in the above-mentionedimage-forming methods should be handled with scrupulous care in thepreparation, the transference or the image formation thereof, becausethe polymerizable compound in the material generally is in a liquidstate or a non-solid state, and the polymerizable compound is sometimescontained in microcapsules which are dispersed in the light-sensitivelayer. Further, the light-sensitive material should be carefullypreserved after the preparation, because the reducing agent in thematerial generally is not a stable compound, and the polymerizablecompound tends to solidify when it is dried or oxidized.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a light-sensitivematerial which is easy to handle and is improved in preservability.

Another object of the invention is to provide a light-sensitive materialwhich gives a clear image.

There is provided by the present invention a light-sensitive materialcomprising a light-sensitive layer which contains silver halide, areducing agent and a polymerizable compound and support, wherein thelight-sensitive layer is provided thereon with a cover sheet.

There is also provided by the invention a light-sensitive materialcomprising the light-sensitive layer which contains silver halide, areducing agent and a polymerizable compound and a support, wherein thelight-sensitive layer is provided thereon with a protective layer.

The light-sensitive material of the invention is characterized in thecover sheet or the protective layer provided on the light-sensitivelayer.

The light-sensitive material on which the cover sheet or the protectivelayer is provided is substantially free from breakage of thelight-sensitive layer in the handling of the material. Therefore, thelight-sensitive material of the invention can be easy to handle in thepreparation, the transference or the image formation thereof.

Further, in the light-sensitive material of the invention, thecomponents of the light-sensitive layer, such as the reducing agent, thepolymerizable compound, are not directly exposed to oxygen and moisturein the air which cause the deterioration of the components. Therefore,the light-sensitive material of the invention can give a clear image,even if the material is preserved for a long term.

Furthermore, in the case that a heat development process is utilized fordeveloping the light-sensitive material, the supply of oxygen into thelight-sensitive layer from outside can be restricted to improve thesensitivity of the light-sensitive material.

DETAILED DESCRIPTION OF THE INVENTION

In the light-sensitive material of the invention, a cover sheet or aprotective layer is provided on the light-sensitive layer. In thisspecification, a sheet (or layer) molded prior to the attachment to thelight-sensitive layer is referred to as the cover sheet, and a layer (orsheet) formed on the light-sensitive layer by coating or lamination isreferred to as the protective layer.

Examples of the low material of the cover sheet include a polymer, metal(e.g., iron, nickel, chromium, copper, aluminum, titanium and an alloyof these metals) and glass. Among them, a transparent material, such asa polymer and glass is preferred, because the light-sensitive materialcan be imagewise exposed to light without removing the transparent coversheet.

In the case that a heat development process is utilized for developingthe light-sensitive material, the cover sheet preferably is anoxygen-impermeable sheet.

The present inventor has found that when supply of oxygen into thelight-sensitive layer from outside is restricted in the heat developmentprocess, the sensitivity of the light-sensitive layer for development isenhanced.

It has been observed that in the heat development process of theabove-mentioned image-forming method, the sensitivity for development islowered by influence of oxygen in the air, because oxygen functions as apolymerization inhibitor and thereby the polymerization reaction of thepolymerizable compound is retarded. In contrast, in a light-sensitivematerial on which the oxygen-impermeable sheet is provided, thepolymerization reaction within the area where the latent image of thesilver halide has been formed (or the area where the latent image of thesilver halide has not been formed) smoothly proceeds to give an image ofhigh quality or to give an image within a short period of time, becausesupply of oxygen into the light-sensitive layer from outside isrestricted.

Further, among the low materials of the cover sheet, the polymer is mostconvenient to handle because of the light weight. Both of a plasticpolymer and a nonplastic polymer, such as a fluororesin (e.g., Teflon,trademark), can be employed. Furthermore, the plastic polymer is mostpreferred, because it is inexpensive and easy to mold to prepare thecover sheet.

Examples of the polymer include polyethylene, polypropylene,polystyrene, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal,polyvinyl fluoride, polyvinyl pyrrolidone, polyvinyl chloride, polyethylacrylate, polymethyl methacrylate, polyethyl methacrylate,polyvinylidene chloride, chlorinated polyethylene, chlorinatedpolypropylene, polycarbonate, polybutadiene, cellulose acetate,cellulose acetate butylate, cellulose acetate propionate, ethylcellulose, benzyl cellulose, cellulose acetate phthalate, polyethyleneterephthalate, polyacrylonitrile, acrylonitrile/styrene copolymer,polymethacrylonitrile, methacrylonitrile/styrene copolymer, polyvinylalcohol, polyvinyl imidazole, polyacrylamide, vinylalcohol/ethylenecopolymer and gelatin.

The thickness of the cover sheet can be determined according to theprotective function, the light transmittance, the transmissioncoefficient of oxygen and the handling. For example, a thick sheet ispreferred with respect to the protective function, but a thin sheet(e.g., not more than 0.2 mm) is preferred with respect to the handling.The cover sheet preferably has a thickness of from 1 μm to 1 mm, andmore preferably from 10 μm to 0.2 mm.

In the case that an oxygen-impermeable sheet is employed as the coversheet to improve the sensitivity of the light-sensitive material, arelatively thin sheet can be employed when the sheet is made of apolymer having a transmission coefficient of oxygen of not more than1.0×10⁻¹¹ cm³ ·cm/cm² ·sec·cmHg.

The transmission coefficient of oxygen follows the definition describedin J. Brandrup, editted by E. H. Immergut, "Polymer Handbook", (1975,III-229). The above value of the transmission coefficient of oxygensubstantially corresponds to not more than about 5×10⁻¹⁰ cm² /secdetermined according to the definition described in K. Petrak, Journalof Applied Polymer Science, Vol. 23, 2365 (1979).

Examples of the above polymer include polyacrylonitrile,acrylonitrile/styrene copolymer, polymethacrylonitrile,methacrylonitrile/styrene copolymer, polyvinyl acetate, polyvinylalcohol, polyvinyl chloride, polyvinylidene chloride, polyvinylimidazole, vinylidene chloride/acrylonitrile copolymer, polyacrylamide,vinyl alcohol/ethylene copolymer (tradename "Eval" produced by KurarayCo., Ltd.) and gelatin.

These polymers are described in the above Polymer Handbook and Journalof Applied Polymer Science.

The above-mentioned cover sheet can be prepared by molding acommercially available sheet for the light-sensitive material. The coversheet can be also made from the low material according to literatures.

The protective layer in the light-sensitive material of the inventionpreferably is a layer containing a polymer. The polymer which may beemployed in the above-mentioned cover sheet is also employable in theprotective layer.

The protective layer preferably is transparent to imagewise expose thelight-sensitive material without removing the protective layer. Further,in the case that a heat development process is utilized for developingthe light-sensitive material, the protective layer preferably containsthe above mentioned polymer having a transmission coefficient of oxygenof not more than 1.0×10⁻¹¹ cm³ ·cm/cm² ·sec·cmHg.

Furthermore, in the case that an unpolymerized polymerizable compoundand/or a color image forming substance is transferred from thelight-sensitive material to an image-receiving material, the protectivelayer preferably is a porous layer. Alternatively, when a thickprotective layer is employed, the unpolymerized polymerizable compoundis transferred to the image-receiving material preferably after theprotective layer is removed from the light-sensitive material. Further,the unpolymerized polymerizable compound can be transferred whileheating the light-sensitive material and the image-receiving material toimprove the transference of the image.

The protective layer can contain a matting agent. Various compoundsincluding a known compounds in the conventional art of photography canbe employed as the matting agent. The matting agent generally means adiscontinuous solid particle made of inorganic or organic material whichcan be dispersed in a hydrophilic organic colloidal binder.

Examples of the inorganic matting agent include an oxidant (e.g.,silicon dioxide, titanium dioxide, magnesium oxide, aluminum oxide), asalt of alkali earth metal, such as sulfate, carbonate (e.g., bariumsulfate, calcium sulfate, magnesium sulfate, calcium carbonate), silverhalide which does not participate in the image formation (e.g., silverchloride, silver bromide, in which a slight amount of silver iodide maybe contained) and glass.

Examples of the organic matting agent include starch, cellulose ester(e.g., cellulose acetate propionate), cellulose ether (e.g., ethylcellulose) and a synthetic resin which preferably is in the form of adispersion of a water-insoluble or slightly water-soluble polymer.Examples of the synthetic resin include alkyl acrylate, alkylmethacrylate, alkoxyalkyl acrylate, alkoxyalkyl methacrylate, glycidylacrylate, glycidyl methacrylate, acrylamide, methacrylamide, vinyl ester(e.g., vinyl acetate), acrylonitrile, an olefin hydrocarbon, styrene, amixture of these polymers and a copolymer comprising a repeating unitderived from one of these polymers and another repeating unit derivedfrom a compound, such as acrylic acid, methacylic acid, α,β-unsaturateddicarboxylic acid, hydroxyalkyl (meth)acrylate, sulfoalkyl(meth)acrylate, stylenesulfonic acid. Among them, polymethylmethacrylate is most preferred.

The matting agent preferably has a mean particle size of from about 0.1to about 10 μm, and more preferably from 0.5 to 8 μm, and mostpreferably from 1 to 6 μm.

The protective layer preferably has a thickness of from 0.1 μm to 50 μm,and more preferably from 0.1 to 5 μm.

The protective layer can be formed by dissolving, emulsifying ordispersing the components, such as the binder in an adequate medium toobtain a coating solution, and then coating the obtained coatingsolution on the light-sensitive layer. Alternatively, the protectivelayer can be also formed on the light-sensitive layer according to aknown method for lamination. In the case that the protective layer isprepared as a porous layer, the coating solution preferably is in theform of a latex in which a polymer is dispersed in a medium.

The silver halide, the reducing agent, the polymerizable compound andthe support which constitute the light-sensitive material of theinvention are described below. Thus composed material is referredhereinafter to as "light-sensitive material".

There is no specific limitation with respect to silver halide containedin the light-sensitive layer of the light-sensitive material.

Examples of the silver halides include as silver chloride, silverbromide, silver iodide, silver chlorobromide, silver chloroiodide,silver iodobromide, and silver chloroiodobromide in the form of grains.

The halogen composition of individual grains may be homogeneous orheterogeneous. The heterogeneous grains having a multilayered structurein which the halogen composition varies from the core to the outer shell(see Japanese Patent Provisional Publication Nos. 57(1982)-154232,58(1983)-108533, 59(1984)-48755 and 59(1984)-52237, U.S. Pat. No.4,433,048, and European Patent No. 100,984) can be employed.

There is no specific limitation on the crystal habit of silver halidegrains. Two or more kinds of silver halide grains which differ inhalogen composition, crystal habit, grain size, and/or other featuresfrom each other can be used in combination. There is no specificlimitation on grain size distribution of silver halide grains. Thesilver halide grains ordinarily have a mean size of 0.001 to 5 μm, morepreferably 0.001 to 2 μm.

The total silver content (including silver halide and an organic silversalt which is one of optional components) in the light-sensitive layerpreferably is in the range of from 0.1 mg/m² to 10 g/m². The silvercontent of the silver halide in the light-sensitive layer preferably isnot more than 0.1 g/m², more preferably in the range of from 1 mg to 90mg/m².

The reducing agent employed in the light-sensitive material has afunction of reducing the silver halide and/or a function of acceleratingor restraining a polymerization of the polymerizable compound. Examplesof the reducing agents having these functions include various compounds,such as hydroquinones, catechols, p-aminophenols, p-phenylenediamines,3-pyrazolidones, 3-aminopyrazoles, 4-amino-5-pyrazolones,5-aminouracils, 4,5-dihydroxy-6-aminopyrimidines, reductones,aminoreductones, o- or p-sulfonamidophenols, o- orp-sulfonamidonaphthols, 2-sulfonamidoindanones,4-sulfonamido-5-pyrazolones, 3-sulfonamidoindoles,sulfonamidopyrazolobenzimidazoles, sulfonamidopyrazolotriazoles,α-sulfonamidoketones, hydrazines, etc. Depending on the nature or amountof the reducing agent, the polymerizable compound within either the areawhere a latent image of the silver halide has been formed or the areawhere a latent image of the silver halide has not been formed can bepolymerized. In the developing system in which the polymerizablecompound within the area where the latent image has not been formed ispolymerized, 1-phenyl-3-pyrazolidone is preferably employed as thereducing agent.

The light-sensitive materials employing the reducing agent having thesefunctions (including compounds referred to as developing agent orhydrazine derivative) are described in Japanese Patent ProvisionalPublication Nos. 61(1986)-183640, 61(1986)-188535 and 61(1986)-228441,and Japanese Patent Application Nos. 60(1985)-210657, 60(1985)-226084,60(1985)-227527 and 60(1985)-227528. These reducing agents are alsodescribed in T. James, "The Theory of the Photographic Process", 4thedition, 291-334 (1977), Research Disclosure No. 17029, 9-15 (Jun.1978), and Research Disclosure No. 17643, 22-31 (Dec. 1978). Thereducing agents described in the these publications and applications canbe employed in the light-sensitive material of the present invention.Thus, "the reducing agent(s)" in the present specification means toinclude all of the reducing agents described in the above mentionedpublications and applications.

These reducing agents can be used singly or in combination. In the casethat two or more reducing agents are used in combination, certaininteractions between these reducing agents may be expected. One of theinteractions is for acceleration of reduction of silver halide (and/oran organic silver salt) through so-called superadditivity. Otherinteraction is for a chain reaction in which an oxidized state of onereducing agent formed by a reduction of silver halide (and/or an organicsilver salt) induces or inhibits the polymerization of the polymerizablecompound via oxidation-reduction reaction with other reducing agent.Both interactions may occur simultaneously. Thus, it is difficult todetermine which of the interactions has occurred in practical use.

Examples of these reducing agents include pentadecylhydroquinone,5-t-butylcatechol, p-(N,N-diethylamino)phenol,1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone,1-phenyl-4-methyl-4-heptadecylcarbonyloxymethyl-3-pyrazolidone,2-phenylsulfonylamino-4-hexadecyloxy-5-t-octylphenol,2-phenylsulfonylamino-4-t-butyl-5-hexadecyloxyphenol,2-(N-butylcarbamoyl)-4-phenylsulfonylaminonaphtol,2-(N-methyl-N-octadecylcarbamoyl)-4-sulfonylaminonaphthol,1-acetyl-2-phenylhydrazine, 1-acetyl-2-(p- or o-aminophenyl)hydrazine,1-formyl-2-(p- or o-aminophenyl)hydrazine, 1-acetyl-2-(p- oro-methoxyphenyl)hydrazine, 1-lauroyl-2-(p- or o-aminophenyl)hydrazine,1-trityl-2-(2,6-dichloro-4-cyanophenyl)hydrazine,1-trityl-2-phenylhydrazine, 1-phenyl-2-(2,4,6-trichlorophenyl)hydrazine,1-{2-(2,5-di-tert-pentylphenoxy)butyloyl}-2-(p- oro-aminophenyl)hydrazine, 1-{2-(2,5-di-t-pentylphenoxy)butyloyl}-2-(p- oro-aminophenyl)hydrazine pentadecylfluorocaprylate salt, 3-indazolinone,1-(3,5-dichlorobenzoyl)-2-phenylhydrazine,1-trityl-2-[{(2-N-butyl-N-octylsulfamoyl)-4-methanesulfonyl}phenyl]hydrazine,1-{4-(2,5-di-tert-pentylphenoxy)butyloyl}-2-(p- oro-methoxyphenyl)hydrazine,1-methoxycarbonylbenzohydryl)-2-phenylhydrazine,1-formyl-2-[4-{2-(2,4-di-tert-pentylphenoxy)butylamide}phenyl]hydrazine,1-acetyl-2-[4-{2-(2,4-di-tert-pentylphenoxy)butylamido}phenyl]hydrazine,1-trityl-2-[{2,6-dichloro-4-(N,N-di-2-ethylhexyl)carbamoyl}phenyl]hydrazine,1-(methoxycarbonylbenzohydryl)-2-(2,4-dichlorophenyl)hydrazine and1-trityl-2-[{2-(N-ethyl-N-octylsulfamoyl)-4-methanesulfonyl}phenyl]hydrazine.

The amount of the reducing agent in the light-sensitive layer preferablyranges from 0.1 to 1,500 mole % based on the amount of silver (containedin the above-mentioned silver halide and an organic silver salt).

There is no specific limitation with respect to the polymerizablecompound, and any known polymerizable compounds including monomers,oligomers and polymers can be contained in the light-sensitive layer. Inthe case that heat development (i.e., thermal development) is utilizedfor developing the light-sensitive material, the polymerizable compoundshaving a relatively higher boiling point (e.g., 80° C. or higher) thatare hardly evaporated upon heating are preferably employed. In the casethat the light-sensitive layer contains a color image forming substance,the polymerizable compounds are preferably cross-linkable compoundshaving plural polymerizable groups in the molecule, because suchcross-linkable compounds favorably serve for fixing the color imageforming substance in the course of polymerization hardening of thepolymerizable compounds.

The polymerizable compounds employable for the light-sensitive materialare described in the above-mentioned and later-mentioned publicationsand applications concerning the light-sensitive material.

Preferred polymerizable compounds employable for the light-sensitivematerial are compounds which are polymerizable through addition reactionor ring-opening reaction. Preferred examples of the compounds beingpolymerizable through addition reaction include compounds having anethylenic unsaturated group. Preferred examples of the compounds beingpolymerizable through ring-opening reaction include the compounds havingan epoxy group. Among them, the compounds having an ethylenicunsaturated group are preferred.

Examples of compounds having an ethylenic unsaturated group includeacrylic acid, salts of acrylic acid, acrylic esters, acrylamides,methacrylic acid, salts of methacrylic acid, methacrylic esters,methacrylamide, maleic anhydride, maleic esters, itaconic esters,styrene, styrene derivatives, vinyl ethers, vinyl esters, N-vinylheterocyclic compounds, allyl ethers, allyl esters, and compoundscarrying a group or groups corresponding to one or more of thesecompounds.

Concrete examples of the acrylic esters include n-butyl acrylate,cyclohexyl acrylate, 2-ethylhexyl acrylate, benzyl acrylate, furfurylacrylate, ethoxyethoxy acrylate, dicyclohexyloxyethyl acrylate,nonylphenyloxyethyl acrylate, hexanediol diacrylate, butanedioldiacrylate, neopentylglycol diacrylate, trimethylolpropane triacrylate,pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate,diacrylate of polyoxyethylenated bisphenol A, polyacrylate ofhydroxypolyether, polyester acrylate, and polyurethane acrylate.

Concrete examples of the methacrylic esters include methyl methacrylate,butyl methacrylate, ethylene glycol dimethacrylate, butanedioldimethacrylate, neopentylglycol dimethacrylate, trimethylolpropanetrimethacrylate, pentaerythritol trimethacrylate, pentaerythritoltetramethacrylate, and dimethacrylate of polyoxyalkylenated bisphenol A.

The polymerizable compounds can be used singly or in combination of twoor more compounds. Further, compounds formed by bonding a polymerizablegroup such as a vinyl group or a vinylidene group to a reducing agent ora color image forming substance are also employed as the polymerizablecompounds. The light-sensitive materials employing these compounds whichshow functions as both the reducing agent and the polymerizablecompound, or of the color image forming substance and the polymerizablecompound are included in embodiments of the invention.

The amount of the polymerizable compound for incorporation into thelight-sensitive layer preferably ranges from 5 to 1.2×10⁵ times (byweight) as much as the amount of silver halide, more preferably from 10to 1×10⁴ times as much as the silver halide.

The light-sensitive material can be prepared by arranging alight-sensitive layer containing the above-mentioned components on asupport. There is no limitation with respect to the support. In the casethat heat development is utilized in the use of the light-sensitivematerial, the material of the support preferably is resistant to heatgiven in the processing stage. Examples of the material employable forthe preparation of the support include glass, paper, fine paper, coatpaper, synthetic paper, metals and analogues thereof, polyester, acetylcellulose, cellulose ester, polyvinyl acetal, polystyrene,polycarbonate, polyethylene terephthalate, and paper laminated withresin or polymer (e.g., polyethylene).

Various embodiments of the light-sensitive materials, optionalcomponents which may be contained in the light-sensitive layer, andauxiliary layers which may be optionally arranged on the light-sensitivematerials are described below.

The polymerizable compound is preferably dispersed in the form of oildroplets in the light-sensitive layer. Other components in thelight-sensitive layer, such as silver halide, the reducing agent, thecolor image forming substances may be also contained in the oildroplets.

The oil droplets of the polymerizable compound are preferably preparedin the form of microcapsules. There is no specific limitation onpreparation of the microcapsules. There is also no specific limitationon shell material of the microcapsule, and various known materials suchas polymers which are employed in conventional microcapsules can beemployed as the shell material. The mean size of the microcapsulepreferably ranges from 0.5 to 50 μm, more preferably 1 to 25 μm, mostpreferably 3 to 20 μm.

The light-sensitive layer can further contain optional components suchas color image forming substances, sensitizing dyes, organic silversalts, various kinds of image formation accelerators, thermalpolymerization inhibitors, thermal polymerization initiators,development stopping agents, fluoroscent brightening agents,discoloration inhibitors, antihalation dyes or pigments, antiirradiationdyes or pigments, matting agents, anti-smudging agents, plasticizers,water releasers and binders.

There is no specific limitation with respect to the color image formingsubstance, and various kinds of substances can be employed. Thus,examples of the color image forming substance include both coloredsubstance (i.e., dyes and pigments) and non-colored or almostnon-colored substance (i.e., color former or dye- or pigment-precursor)which develops to give a color under application of external energy(e.g., heating, pressing, light irradiation, etc.) or by contact withother components (i.e., developer). The light-sensitive material usingthe color image forming substance is described in Japanese PatentProvisional Publication No. 61(1986)-73145.

Examples of the dyes and pigments (i.e., colored substances) employablein the invention include commercially available ones, as well as variousknown compounds described in the technical publications, e.g., YukiGosei Kagaku Kyokai (ed.), Handbook of Dyes (in Japanese, 1970) andNippon Ganryo Gijutsu Kyokai (ed.), New Handbook of Pigments (inJapanese, 1977). These dyes and pigments can be used in the form of asolution or a dispersion.

Examples of the substances which develop to give a color by certainenergy includes thermochromic compounds, piezochromic compounds,photochromic compounds and leuco compounds derived from triarylmethanedyes, quinone dyes, indigoid dyes, azine dyes, etc. These compounds arecapable of developing a color by heating, application of pressure,light-irradiation or air-oxidation.

Examples of the substances which develop to give a color in contact withother components include various compounds capable of developing a colorthrough some reaction between two or more components, such as acid-basereaction, oxidation-reduction reaction, coupling reaction, chelatingreaction, and the like. Examples of such color formation systems aredescribed in Hiroyuki Moriga, "Introduction of Chemistry of SpecialityPaper" (in Japanese, 1975), 29-58 (pressure-sensitive copying paper),87-95 (azo-graphy), 118-120 (heat-sensitive color formation by achemical change) or in MSS. of the seminer promoted by the Society ofKinki Chemical Industry, "The Newest Chemistry of ColoringMatter-Attractive Application and New Development as a FunctionalColoring Matter", 26-32 (Jun. 19, 1980). Examples of the color formationsystems specifically include a color formation system used inpressure-sensitive papers, etc., comprising a color former having apartial structure of lactone, lactam, spiropyran, etc., and an acidicsubstance (developer), e.g., acid clay, phenol, etc.; a system utilizingazo-coupling reaction between an aromatic a diazonium salt, diazotate ordiazosulfonate and naphthol, aniline, active methylene, etc.; a systemutilizing a chelating reaction, such as a reaction betweenhexamethylenetetramine and a ferric ion and gallic acid, or a reactionbetween a phenolphthalein-complexon and an alkaline earth metal ion; asystem utilizing oxidation-reduction reaction, such as a reactionbetween ferric stearate and pyrogallol, or a reaction between silverbehenate and 4-methoxy-1-naphthol, etc.

The color image forming substance in the light-sensitive material ispreferably used in an amount of from 0.5 to 50 parts by weight, and morepreferably from 2 to 30 parts by weight, per 100 parts by weight of thepolymerizable compound. In the case that the developer is used, it ispreferably used in an amount of from about 0.3 to about 80 parts byweight per one part by weight of the color former.

There is no specific limitation with respect to the sensitizing dyes,and known sensitizing dyes used in the conventional art of photographymay be employed in the light-sensitive material. Examples of thesensitizing dyes include methine dyes, cyanine dyes, merocyanine dyes,complex cyanine dyes, complex merocyanine dyes, holopolar cyanine dyes,hemicyanine dyes, styryl dyes, and hemioxonol dyes. These sensitizingdyes can be used singly or in combination. Combinations of sensitizingdyes are often used for the purpose of supersensitization. In additionto the sensitizing dyes, a substance which does not per se exhibitspectral sensitization effect or does not substantially absorb visiblelight but shows supersensitizing activity can be used. The amount of thesensitizing dye to be added generally ranges from about 10⁻⁸ to about10⁻² mol per 1 mol of silver halide. The sensitizing dye is preferablyadded during the stage of the preparation of the silver halide emulsion.

When the heat development is employed in the use of the light-sensitivematerial, an organic silver salt is preferably contained in thelight-sensitive material. It can be assumed that the organic silver salttakes part in a redox reaction using a silver halide latent image as acatalyst when heated to a temperature of 80° C. or higher. In such case,the silver halide and the organic silver salt preferably are located incontact with each other or close together. Examples of organic compoundsemployable for forming such organic silver salt include aliphatic oraromatic carboxylic acids, thiocarbonyl group-containing compoundshaving a mercapto group or an α-hydrogen atom, imino group-containingcompounds, and the like. Among them, benzotriazoles are most preferable.The organic silver salt is preferably used in an amount of from 0.01 to10 mol., and preferably from 0.01 to 1 mol., per 1 mol. of thelight-sensitive silver halide. Instead of the organic silver salt, anorganic compound (e.g., benzotriazole) which can form an organic silversalt in combination with an inorganic silver salt can be added to thelight-sensitive layer to obtain the same effect.

Various image formation accelerators are employable in thelight-sensitive material. The image formation accelerators have afunction to accelerate the oxidation-reduction reaction between a silverhalide (and/or an organic silver salt) and a reducing agent, a functionto accelerate emigration of an image forming substance from alight-sensitive layer to an image-receiving material or animage-receiving layer, or a similar function. The image formationaccelerators can be classified into inorganic bases, organic bases, baseprecursors, oils, surface active agents, hot-melt solvents, and thelike. These groups, however, generally have certain combined functions,i.e., two or more of the above-mentioned effects. Thus, the aboveclassification is for the sake of convenience, and one compound oftenhas a plurality of functions combined.

Various examples of these image formation accelerators are shown below.

Preferred examples of the inorganic bases include hydroxides of alkalimetals or alkaline earth metals; secondary or tertiary phosphates,borates, carbonates, quinolinates and metaborates of alkali metals oralkaline earth metals; a combination of zinc hydroxide or zinc oxide anda chelating agent (e.g., sodium picolinate); ammonium hydroxide;hydroxides of quaternary alkylammoniums; and hydroxides of other metals.Preferred examples of the organic bases include aliphatic amines (e.g.,trialkylamines, hydroxylamines and aliphatic polyamines); aromaticamines (e.g., N-alkyl-substituted aromatic amines,N-hydroxylalkyl-substituted aromatic amines andbis[p-(dialkylamino)phenyl]-methanes), heterocyclic amines, amidines,cyclic amidines, guanidines, and cyclic guanidines. Of these bases,those having a pKa of 7 or more are preferred.

The base precursors preferably are those capable of releasing bases uponreaction by heating, such as salts between bases and organic acidscapable of decarboxylation by heating, compounds capable of releasingamines through intramolecular nucleophilic substitution, Lossenrearrangement, or Beckmann rearrangement, and the like; and thosecapable of releasing bases by electrolysis. Preferred examples of thebase precursors include guanidine trichloroacetate, piperidinetrichloroacetate, morpholine trichloroacetate, p-toluidinetrichloroacetate, 2-picoline trichloroacetate, guanidinephenylsulfonylacetate, guanidine 4-chlorophenylsulfonylacetate,guanidine 4-methyl-sulfonylphenylsulfonylacetate, and4-acetylaminomethyl propionate.

These bases or base precursors are preferably used in an amount of notmore than 100% by weight, and more preferably from 0.1 to 40% by weight,based on the total solid content of the light-sensitive layer. Thesebases or base precursors can be used singly or in combination.

Examples of the oils employable in the invention include high-boilingorganic solvents which are used as solvents in emulsifying anddispersing hydrophobic compounds.

Examples of the surface active agents employable in the inventioninclude pyridinium salts, ammonium salts and phosphonium salts asdescribed in Japanese Patent Provisional Publication No. 59(1984)-74547;polyalkylene oxides as described in Japanese Patent ProvisionalPublication No. 59(1984)-57231.

The hot-melt solvents preferably are compounds which may be used assolvent of the reducing agent or those which have high dielectricconstant and can accelerate physical development of silver salts.Examples of the hot-melt solvents include polyethylene glycols,derivatives of polyethylene oxides (e.g., oleate ester), beeswax,monostearin and high dielectric constant compounds having --SO₂ --and/or --CO-- group described in U.S. Pat. No. 3,347,675; polarcompounds described in U.S. Pat. No. 3,667,959; and 1,10-decanediol,methyl anisate and biphenyl suberate described in Research Disclosure26-28 (Dec. 1976). The light-sensitive material employing the hot-meltsolvents is described in Japanese Patent Application No.60(1985)-227527. The hot-melt solvent is preferably used in an amount offrom 0.5 to 50% by weight, and more preferably from 1 to 20% by weight,based on the total solid content of the light-sensitive layer.

The thermal polymerization initiators employable in the light-sensitivematerial preferably are compounds that are decomposed under heating togenerate a polymerization initiating species, particularly a radical,and those commonly employed as initiators of radical polymerization. Thethermal polymerization initiators are described in "AdditionPolymerization and Ring Opening Polymerization", 6-18, edited by theEditorial Committee of High Polymer Experimental Study of the HighPolymer Institute, published by Kyoritsu Shuppan (1983). Examples of thethermal polymerization initiators include azo compounds, e.g.,azobisisobutyronitrile, 1,1'-azobis(1-cyclohexanecarbonitrile), dimethyl2,2'-azobisisobutyrate, 2,2'-azobis(2-methylbutyronitrile), andazobisdimethylvaleronitrile; organic peroxides, e.g., benzoyl peroxide,di-tert-butyl peroxide, dicumyl peroxide, tertbutyl hydroperoxide, andcumene hydroperoxide; inorganic peroxides, e.g., hydrogen peroxide,potassium persulfate, and ammonium persulfate; and sodiump-toluenesulfinate. The thermal polymerization initiators are preferablyused in an amount of from 0.1 to 120% by weight, and more preferablyfrom 1 to 10% by weight, based on amount of the polymerizable compound.In a system in which the polymerizable compound within the area wherethe latent image has not been formed is polymerized, the thermalpolymerization initiators are preferably incorporated into thelight-sensitive layer. The light-sensitive material employing thethermal polymerization initiators is described in Japanese PatentProvisional Publication No. 61(1986)-260241.

The development stopping agents employable in the light-sensitivematerial are compounds that neutralize a base or react with a base toreduce the base concentration in the layer to thereby stop development,or compounds that mutually react with silver or a silver salt tosuppress development. More specifically, examples of the developmentstopping agents include acid precursors capable of releasing acids uponheating electrophilic compounds capable of undergoing substitutionreaction with a coexisting base upon heating, nitrogen-containingheterocyclic compounds, mercapto compounds, and the like. Examples ofthe acid precursors include oxide esters described in Japanese PatentProvisional Publication Nos. 60(1985)-108837 and 60(1985)-192939 andcompounds which release acids through Lossen rearrangement described inJapanese Patent Provisional Publication No. 60(1985)-230133. Examples ofthe electrophilic compounds which induce substitution reaction withbases upon heating are described in Japanese Patent ProvisionalPublication No. 60(1985)-230134.

The antismudging agents employable in the light-sensitive materialpreferably are particles which are solid at ambient temperatures.Examples of the antismudging agents include starch particles describedin U.K. Patent No. 1,232,347; polymer particles described in U.S. Pat.No. 3,625,736; microcapsule particles containing no color formerdescribed in U.K. Patent No. 1,235,991; and cellulose particles, andinorganic particles, such as particles of talc, kaolin, bentonite,agalmatolite, zinc oxide, titanium dioxide or aluminum oxide describedin U.S. Pat. No. 2,711,375. Such particles preferably have a mean sizeof 3 to 50 μm, more preferably 5 to 40 μm. When the microcapsule isemployed in the light-sensitive material, the size of said particle ispreferably larger than that of the microcapsule.

Binders employable in the light-sensitive material preferably aretransparent or semi-transparent hydrophilic binders. Examples of thebinders include natural substances, such as gelatin, gelatinderivatives, cellulose derivatives, starch, and gum arabic; andsynthetic polymeric substances, such as water-soluble polyvinylcompounds e.g., polyvinyl alcohol, polyvinylpyrrolidone, and acrylamidepolymers. In addition to the synthetic polymeric substances, vinylcompounds dispersed in the form of latex, which are particularlyeffective to increase dimensional stability of photographic materials,can be also used. These binders can be used singly or in combination.The light-sensitive material employing a binder is described in JapanesePatent Provisional Publication No. 61(1986)-69062.

Examples and usage of the other optional components which can becontained in the light-sensitive layer are also described in theabove-mentioned publications and applications concerning thelight-sensitive material, and in Research Disclosure Vol. 170, No.17029, 9-15 (Jun. 1978).

Examples of auxiliary layers which are optionally arranged on thelight-sensitive material include an image-receiving layer, a heatinglayer, an antistatic layer, an anticurl layer and a release layer.

Instead of the use of the image-receiving material, the image-receivinglayer can be arranged on the light-sensitive material to produce thedesired image on the image-receiving layer of the light-sensitivematerial. The image-receiving layer of the light-sensitive material canbe constructed in the same manner as the layer of the image-receivingmaterial.

The light-sensitive material can be prepared, for instance, by thefollowing process.

The light-sensitive material is usually prepared by dissolving,emulsifying or dispersing each of the components of the light-sensitivelayer in an adequate medium to obtain coating solution, and then coatingthe obtained coating solution on a support.

The coating solution can be prepared by mixing liquid compositions eachcontaining a component of the light-sensitive layer. Liquid compositionscontaining two or more components may be also used in the preparation ofthe coating solution. Some components of the light-sensitive layer canbe directly added to the coating solution or the liquid composition.Further, a secondary composition can be prepared by emulsifying the oily(or aqueous) composition in an aqueous (or oily) medium to obtain thecoating solution.

The silver halide is preferably prepared in the form of a silver halideemulsion. Various processes for the preparation of the silver halideemulsion are known in the conventional technology for the preparation ofphotographic materials.

The silver halide emulsion can be prepared by the acid process, neutralprocess or ammonia process. In the stage for the preparation, a solublesilver salt and a halogen salt can be reacted in accordance with thesingle jet process, double jet process or a combination thereof. Areverse mixing method, in which grains are formed in the presence ofexcess silver ions, or a controlled double jet process, in which a pAgvalue is maintained constant, can be also employed. In order toaccelerate grain growth, the concentrations or amounts or the silversalt and halogen salt to be added or the rate of their addition can beincreased as described in Japanese Patent Provisional Publication Nos.55(1980)-142329 and 55(1980)-158124, and U.S. Pat. No. 3,650,757, etc.

The silver halide emulsion may be of a surface latent image type thatforms a latent image predominantly on the surface of silver halidegrains, or of an inner latent image type that forms a latent imagepredominantly in the interior of the grains. A direct reversal emulsioncomprising an inner latent image type emulsion and a nucleating agentmay be employed. The inner latent image type emulsion suitable for thispurpose is described in U.S. Pat. Nos. 2,592,250 and 3,761,276, JapanesePatent Publication No. 58(1983)-3534 and Japanese Patent ProvisionalPublication No. 57(1982)-136641, etc. The nucleating agent that ispreferably used in combination with the inner latent image type emulsionis described in U.S. Pat. Nos. 3,227,552, 4,245,037, 4,255,511,4,266,013 and 4,276,364, and West German Patent Provisional Publication(OLS) No. 2,635,316.

In the preparation of the silver halide emulsions, hydrophilic colloidsare advantageously used as protective colloids. Examples of usablehydrophilic colloids include proteins, e.g., gelatin, gelatinderivatives, gelatin grafted with other polymers, albumin, and casein;cellulose derivatives, e.g., hydroxyethyl cellulose, carboxymethylcellulose, cellulose sulfate, etc.; saccharide derivatives, e.g., sodiumalginate and starch derivatives; and a wide variety of synthetichydrophilic polymers, such as polyvinyl alcohol, polyvinyl alcoholpartial acetal, poly-N-vinylpyrrolidone, polyacrylic acid,polymethacrylic acid, polyacrylamide, polyvinylimidazole, andpolyvinylpyrazole, and copolymers comprising monomers constituting thesehomopolymers. Among them, gelatin is most preferred. Examples ofemployable gelatins include not only lime-processed gelatin, but alsoacid-processed gelatin and enzyme-processed gelatin. Hydrolysis productsor enzymatic decomposition products of gelatin can also be used.

In the formation of silver halide grains in the silver halide emulsion,ammonia, an organic thioether derivative as described in Japanese PatentPublication No. 47(1972)-11386 or sulfur-containing compound asdescribed in Japanese Patent Provisional Publication No. 53(1978)-144319can be used as a silver halide solvent. Further, in the grain formationor physical ripening, a cadmium salt, a zinc salt, a lead salt, athallium salt, or the like can be introduced into the reaction system.Furthermore, for the purpose of improving high or low intensityreciprocity law failure, a water-soluble iridium salt, e.g., iridium(III) or (IV) chloride, or ammonium hexachloroiridate, or awater-soluble rhodium salt, e.g., rhodium chloride can be used.

After the grain formation or physical ripening, soluble salts may beremoved from the resulting emulsion by a known noodle washing method ora sedimentation method. The silver halide emulsion may be used in theprimitive condition, but is usually subjected to chemical sensitization.Chemical sensitization can be carried out by the sulfur sensitization,reduction sensitization or noble metal sensitization, or a combinationthereof that are known for emulsions for the preparation of theconventional light-sensitive materials.

When the sensitizing dyes are added to the silver halide emulsion, thesensitizing dye is preferably added during the preparation of theemulsion. When the organic silver salts are introduced in thelight-sensitive microcapsule, the emulsion of the organic silver saltscan be prepared in the same manner as in the preparation of the silverhalide emulsion.

In preparation of the light-sensitive material, the polymerizablecompounds are used as the medium for preparation of the liquidcomposition containing another component of the light-sensitive layer.For example, the silver halide, including the silver halide emulsion),the reducing agent, or the color image forming substance can bedissolved, emulsified or dispersed in the polymerizable compound toprepare the light-sensitive material. Especially, the color imageforming substance is preferably incorporated in the polymerizablecompound. Further, the necessary components for preparation of amicrocapsule, such as shell material can be incorporated into thepolymerizable compound.

The light-sensitive composition which is the polymerizable compoundcontaining the silver halide can be prepared using the silver halideemulsion. The light-sensitive composition can be also prepared usingsilver halide powders which can be prepared by lyophilization. Theselight-sensitive composition can be obtained by stirring thepolymerizable compound and the silver halide using a homogenizer, ablender, a mixer or other conventional stirring device.

Polymers having a principal chain consisting essentially of ahydrocarbon chain substituted in part with hydrophilic groups whichcontain, in their terminal groups, --OH or nitrogen having a loneelectron-pair are preferably introduced into the polymerizable compoundprior to the preparation of the light-sensitive composition. The polymerhas a function of dispersing silver halide or other component in thepolymerizable compound very uniformly as well as a function of keepingthus dispered state. Further, the polymer has another function ofgathering silver halide along the interface between the polymerizablecompound (i.e., light-sensitive composition) and the aqueous medium inpreparation of the microcapsule. Therefore, using this polymer, silverhalide can be easily introduced into the shell material of themicrocapsule.

The polymerizable compound (including the light-sensitive composition)are preferably emulsified in an aqueous medium to prepare the coatingsolution. The necessary components for preparation of the microcapsule,such as shell material can be incorporated into the emulsion. Further,other components such as the reducing agent can be added to theemulsion.

The emulsion of the polymerizable compound can be processed for formingshell of the microcapsule. Examples of the process for the preparationof the microcapsules include a process utilizing coacervation ofhydrophilic wall-forming materials as described in U.S. Pat. Nos.2,800,457 and 2,800,458; an interfacial polymerization process asdescribed in U.S. Pat. No. 3,287,154, U.K. Patent No. 990,443 andJapanese Patent Publication Nos. 38(1963)-19574, 42(1967)-446 and42(1967)-771; a process utilizing precipitation of polymers as describedin U.S. Pat. Nos. 3,418,250 and 3,660,304; a process of usingisocyanate-polyol wall materials as described in U.S. Pat. No.3,796,669; a process of using isocyanate wall materials as described inU.S. Pat. No. 3,914,511; a process of using urea-formaldehyde orurea-formaldehyde-resorcinol wall-forming materials as described in U.S.Pat. Nos. 4,001,140, 4,087,376 and 4,089,802; a process of usingmelamine-formaldehyde resins hydroxypropyl cellulose or likewall-forming materials as described in U.S. Pat. No. 4,025,455; an insitu process utilizing polymerization of monomers as described in U.K.Patent No. 867,797 and U.S. Pat. No. 4,001,140; an electrolyticdispersion and cooling process as described in U.K. Patent Nos. 952,807and 965,074; a spray-drying process as described in U.S. Pat. No.3,111,407 and U.K. Patent 930,422; and the like. It is preferable,though not limitative, that the microcapsule is prepared by emulsifyingcore materials containing the polymerizable compound and forming apolymeric membrane (i.e., shell) over the core materials.

When the emulsion of the polymerizable compound (including thedispersion of the microcapsule) has been prepared by using thelight-sensitive composition, the emulsion can be used as the coatingsolution of the light-sensitive material. The coating solution can bealso prepared by mixing the emulsion of the polymerizable compound andthe silver halide emulsion.

A light-sensitive layer can be formed by coating and drying theabove-prepared coating solution on a support in the conventional manner.

The light-sensitive material of the invention is prepared by providing acover sheet or a protective layer on the light-sensitive layer.

An under coating layer can be formed on the light-sensitive layer priorto the attachment of the cover sheet to enhance the adhesion between thelight-sensitive layer and the cover sheet. Further, the surface of thecover sheet can be processed with a physical or chemical treatment toenhance the adhesion.

The protective layer can be formed by coating or lamination as mentionedabove.

Use of the light-sensitive material is described below.

In the use of the light-sensitive material of the invention, adevelopment process is conducted simultaneously with or after animagewise exposure.

Various exposure means can be employed in the image-wise exposure, andin general, the latent image on the silver halide is obtained byimagewise exposure to radiation including visible light. The type oflight source and exposure can be selected depending on thelight-sensitive wavelengths determined by spectral sensitization orsensitivity of silver halide. Original image can be either monochromaticimage or color image.

The light-sensitive material can be imagewise exposed after the coversheet (especially in the case that the cover sheet is not transparent)is removed.

Development of the light-sensitive material can be conductedsimultaneously with or after the imagewise exposure. The development canbe conducted using a developing solution in the same manner as the imageforming method described in Japanese Patent Publication No.45(1970)-11149. The image forming method described in Japanese PatentProvisional Publication No. 61(1986)-69062 which employs a heatdevelopment process has an advantage of simple procedures and shortprocessing time because of the dry process. Thus, the latter method ispreferred as the development process of the light-sensitive material.

Heating in the heat development process can be conducted in variousknown manners. The heating layer which is arranged on thelight-sensitive material can be used as the heating means in the samemanner as the light-sensitive material described in Japanese PatentApplication No. 60(1985)-135568. Heating temperatures for thedevelopment process usually ranges from 80° C. to 200° C., andpreferably from 100° C. to 160° C. Various heating patterns areapplicable. The heating time is usually from 1 second to 5 minutes, andpreferably from 5 seconds to 1 minute.

During the above development process, a polymerizable compound in aportion where a latent image of the silver halide has been formed or ina portion where a latent image of the silver halide has not been formedis polymerized. In a general system, the polymerizable compound in aportion where the latent image has been formed is polymerized. If anature or amount of the reducing agent is controlled, the polymerizablecompound in a portion where the latent image has not been formed can bepolymerized in the same manner as the light-sensitive material describedin Japanese Patent Application No. 61(1986)-243449 (corresponding toU.S. patent Ser. No. 854,640).

In the case that the cover sheet or the protective layer is anoxygen-impermeable sheet or layer, the supply of oxygen into thelight-sensitive layer can be restricted in the heat development processto improve the sensitivity, as mentioned above.

In the above development process, a polymer image can be formed on thelight-sensitive layer. A pigment image can be also obtained by fixingpigments to the polymer image.

Further, a color image can be formed on the light-sensitive material inwhich the light-sensitive layer contains a color former and a developer,one of them is together with the polymerizable compound contained in amicrocapsule, and the other is arranged outside of the microcapsule. Inthe cover sheet or the protective layer is an oxygen-impermeable sheetor layer, the sheet or layer can function of protecting the obtainedimage after the image-formation. The present inventor has found that thediscoloration of the obtained color image is caused by deterioration ofthe developed color former, and that the deterioration is aphotochemical reaction in presence of oxygen. Therefore, the color ofthe image formed on the light-sensitive layer can be protected by theoxygen-impermeable sheet or layer.

The image can be also formed on the image-receiving material. Theimage-receiving material is described hereinbelow. The image formingmethod employing the image-receiving material or the image-receivinglayer is described in Japanese Patent Provisional Publication No.61(1986)-278849 (corresponding to U.S. patent Ser. No. 868,385).

Examples of the material employable as the support of theimage-receiving material include baryta paper in addition to variousexamples which can be employed as the support of the knownlight-sensitive material.

The image-receiving material is usually prepared by providing theimage-receiving layer on the support. The image-receiving layer can beconstructed according to the color formation system. In the cases that apolymer image is formed on the image-receiving material and that a dyeor pigment is employed as the color image forming substance, theimage-receiving material be composed of a simple support.

For example, when a color formation system using a color former anddeveloper is employed, the developer can be contained in theimage-receiving layer. Further, the image-receiving layer can becomposed of at least one layer containing a mordant. The mordant can beselected from the compounds known in the art of the conventionalphotography according to the kind of the color image forming substance.If desired, the image-receiving layer can be composed of two or morelayers containing two or more mordants different in the mordanting powerfrom each other.

The image-receiving layer preferably contains a polymer as binder. Thebinder which may be employed in the above-mentioned light-sensitivelayer is also employable in the image-receiving layer.

The image-receiving layer can be composed of two or more layersaccording to the above-mentioned functions. The thickness of theimage-receiving layer preferably ranges from 1 to 100 μm, morepreferably from 1 to 20 μm.

After the development process, pressing the light-sensitive material onthe image-receiving material to transfer the unpolymerized polymerizablecompound to the image-receiving material, a polymer image can beobtained in the image-receiving material. The process for pressing canbe carried out in various known manners.

In the case that the light-sensitive layer contains a color imageforming substance, the color image forming substance is fixed bypolymerization of the polymerizable compound. Then, pressing thelight-sensitive material on the image-receiving material to transfer thecolor image forming substance in unfixed portion, a color image can beproduced on the image-receiving material.

The light-sensitive material can be used for monochromatic or colorphotography, printing, radiography, diagnosis (e.g., CRT photography ofdiagnostic device using supersonic wave), copy (e.g., computer-graphichard copy), etc.

The present invention is further described by the following exampleswithout limiting the invention.

COMPARISON EXAMPLE 1 Preparation of silver halide emulsion

In 1,000 ml of water were dissolved 20 g of gelatin and 3 g of sodiumchloride, and the resulting gelatin solution was kept at 75° C. To thegelatin solution, 600 ml of an aqueous solution containing 21 g ofsodium chloride and 56 g of potassium bromide and 600 ml of an aqueoussolution containing 0.59 mole of silver nitrate were addedsimultaneously at the same feed rate over a period of 40 minutes toobtain a silver chlorobromide emulsion having cubic grains, uniformgrain size distribution, a mean grain size of 0.35 μm and a bromidecontent of 80 mole %.

The emulsion was washed for desalting and then subjected to chemicalsensitization with 5 mg of sodium thiosulfate and 20 mg of4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene at 60° C. The yield of theemulsion was 600 g.

Preparation of silver benzotriazole emulsion

In 3,000 ml of water were dissolved 28 g of gelatin and 13.2 g ofbenzotriazole, and the solution was kept at 40° C. while stirring. Tothe solution was added 100 ml of an aqueous solution of 17 g of silvernitrate over 2 min. Excess salts were sedimented and removed from theresulting emulsion by pH adjustment. Thereafter, the emulsion wasadjusted to a pH of 6.30 to obtain a silver benzotriazole emulsion. Theyield of the emulsion was 400 g.

Preparation of light-sensitive composition

In 100 g of trimethylolpropane triacrylate were dissolved 0.40 g of thefollowing copolymer, 6.00 g of Pargascript Red I-6-B (tradename ofCiba-Geigy) and 2 g of Emulex NP-8 (tradename, produced by NipponEmulsion Co., Ltd.). ##STR1##

In 18.00 g of the resulting solution was dissolved 0.002 g of thefollowing thiol derivative. ##STR2##

To the resulting solution was added a solution in which 0.16 g of thefollowing reducing agent (I) and 1.22 g of the following reducing agent(II) are dissolved in 1.80 g of methylene chloride. ##STR3##

Further, to the resulting solution were added 3.50 g of the silverhalide emulsion and 3.35 g of the silver benzotriazole emulsion, and themixture was stirred at 15,000 r.p.m. for 5 minutes to obtain alight-sensitive composition.

Preparation of light-sensitive microcapsule

To 10.51 g of 18.6% aqueous solution of Isobam (tradename, produced byKuraray Co., Ltd.) was added 48.56 g of 2.89% aqueous solution ofpectin. After the solution was adjusted to a pH of 4.0 using 10%sulfuric acid, the light-sensitive composition was added to theresulting solution, and the mixture was stirred at 7,000 r.p.m. for 2min. to emulsify the light-sensitive composition in the aqueous medium.

To 72.5 g of the aqueous emulsion were added 8.32 g of 40% aqueoussolution of urea, 2.82 g of 11.3% aqueous solution of resorcinol, 8.56 gof 37% aqueous solution of formaldehyde, and 2.74 g of 8.76% aqueoussolution of ammonium sulfate in this order, and the mixture was heatedat 60° C. for 2 hours while stirring. After the mixture was adjusted toa pH of 7.0 using 10% aqueous solution of sodium hydroxide, 3.62 g of30.9% aqueous solution of sodium hydrogen sulfite was added to themixture to obtain a dispersion containing light-sensitive microcapsules.

Preparation of light-sensitive material

To 10.0 g of the light-sensitive microcapsule dispersion were added 1.0g of 1% aqueous solution of the following anionic surfactant and 1.0 gof 10% solution (solvent: water/ethanol=50/50 as volume ratio) ofguanidine trichroloacetate to prepare a coating solution. ##STR4##

The coating solution was uniformly coated on a polyethyleneterephthalate film (thickness: 100 μm) using a coating rod of #40 togive a layer having a wet thickness of 70 μm and dried at about 40° C.to obtain a light-sensitive material (A).

Preparation of image-receiving material

To 125 g of water was added 11 g of 40% aqueous solution of sodiumhexametaphosphate, and were further added 34 g of zinc3,5-di-α-methylbenzylsalicylate and 82 g of 55% slurry of calciumcarbonate, followed by coarsely dispersing in a mixer. The coarsedispersion was then finely dispersed in Dynomill dispersing device. To200 g of the resulting dispersion were added 6 g of 50% latex of SBR(styrene-butadiene rubber) and 55 g of 8% aqueous solution of polyvinylalcohol, and the resulting mixture was made uniform.

The mixture was then uniformly coated on an art paper having a basisweight of 43 g/m² to give a layer having a wet thickness of 30 μm anddried to obtain an image-receiving material.

Evaluation of light-sensitive material

The light-sensitive material (A) was imagewise exposed to light using atungsten lamp at 200 lux for 1 second and then heated on a hot plate at125° C. for 40 seconds. The exposed and heated light-sensitive materialwas then combined with the image-receiving material and passed throughpress rolls under pressure of 350 kg/cm² to obtain a magenta positiveimage on the image receiving material. The density of the obtained imagewas measured using Macbeth reflection densitometer. Each of the maximumdensity and the minimum density respectively was 1.41 and 0.20. Further,the sensitivity of the obtained image was supposed to have a relativevalue of 100 to determine the relative sensitivity.

EXAMPLE 1 Preparation of light-sensitive material

The light-sensitive material (B) was prepared by attaching apolyethylene terephthalate film (thickness: 100 μm) on thelight-sensitive layer of the light-sensitive material (A) prepared inComparison Example 1.

Evaluation of light-sensitive material

The light-sensitive material (B) was imagewise exposed to light using atungsten lamp at 200 lux for 1 second and then heated on a hot plate at125° C. for 40 seconds. In these processes, the light-sensitive materialwas easily handled, because the cover sheet (polyethylene terephthalatefilm) was attached on the light-sensitive layer. After the cover sheetwas removed, the exposed and heated light-sensitive material was thencombined with the image-receiving material and passed through pressrolls under pressure of 350 kg/cm² to obtain a clear magenta positiveimage on the image receiving material. The density of the obtained imagewas measured using Macbeth reflection densitometer. Each of the maximumdensity and the minimum density was the same as in Comparison Example 1.However, the relative sensitivity of the obtained image increased to350.

COMPARISON EXAMPLE 2 Preparation of silver halide emulsion

In 3 l of water were dissolved 40 g of gelatin and 23.8 g of potassiumbromide and the resulting gelatin solution was kept at 50° C. To thegelatin solution, 200 ml of an aqueous solution containing 34 g ofsilver nitrate was added over a period of 10 minutes while stirring. Tothe solution, 100 ml of an aqueous solution containing 3.3 g ofpotassium iodide was added over a period of 2 minutes to obtain a silverbromoiodide emulsion. After the emulsion was adjusted to a pH forsedimentation, excess salts were removed, and the emulsion was adjustedto a pH of 6.0. The yield of the emulsion was 400 g.

Preparation of light-sensitive composition

In 100 g of trimethylolpropane triacrylate were dissolved 0.40 g of thecopolymer used in Comparison Example 1 and 6.00 g of Pargascript RedI-6-B (tradename of Ciba-Geigy). In 18.00 g of the obtained solution wasadded a solution in which 0.16 g of the reducing agent (I) and 1.22 g ofthe reducing agent (II) both used in Comparison Example 1 are dissolvedin 1.80 g of methylene chloride. Further, to the resulting solution wasadded a mixture which is prepared by mixing 4.06 g of the above silverhalide emulsion and 0.6 ml of a 0.04% methanol solution of following dyeand stirred for 5 minutes, and the resulting mixture was stirred at15,000 r.p.m. for 5 min. to obtain a light-sensitive composition.##STR5##

Preparation of light-sensitive microcapsule

Dispersion of light-sensitive microcapsule was prepared in the samemanner as in Comparison Example 1 except that the above light-sensitivecomposition was used.

Preparation of light-sensitive material

A light-sensitive material (C) was prepared in the same manner as inComparison Example 1 except that the above light-sensitive microcapsulewas used.

Evaluation of light-sensitive material

The light-sensitive material (C) was imagewise exposed to light througha green filter which transmits a light having a wavelength from 500 to600 nm and in which the density continuously changed, using a tungstenlamp at 2,000 lux for 1 second and then heated on a hot plate at 125° C.for 20 seconds. The exposed and heated light-sensitive materials wasthen combined with the image-receiving material and passed through pressrolls under pressure of 350 kg/cm² to obtain a magenta positive image onthe image receiving element. The density of the obtained image wasmeasured using Macbeth reflection densitometer. Each of the maximumdensity and the minimum density respectively was 1.41 and 0.19. Further,the sensitivity of the obtained image was supposed to have a relativevalue of 100 to determine the relative sensitivity.

EXAMPLE 2 Preparation of light-sensitive material

The light-sensitive material (D) was prepared by coating 3% aquesoussolution of polyvinyl alcohol (degree of polymerization: 2,000) on thelight-sensitive layer of the light-sensitive material (C) prepared inComparison Example 2 to give a layer having a wet thickness of 3 μm anddrying the obtained layer.

Evaluation of light-sensitive material

The light-sensitive material (D) was imagewise exposed to light througha green filter which transmits a light having a wavelength from 500 to600 nm and in which the density continuously changed, using a tungstenlamp at 2,000 lux for 1 second and then heated on a hot plate at 125° C.for 20 seconds. The exposed and heated light-sensitive materials wasthen combined with the image-receiving material and passed through pressrolls under pressure of 500 kg/cm² to obtain a clear magenta positiveimage on the image receiving element. The density of the obtained imagewas measured using Macbeth reflection densitometer. Each of the maximumdensity and the minimum density respectively was 1.15 and 0.20. Therelative sensitivity of the obtained image increased to 350. In theseprocess, the light-sensitive material was easily handled, because theprotective layer was provided on the light-sensitive layer.

EXAMPLE 3 Preparation of light-sensitive material

The light-sensitive material (E) was prepared by coating 3% aqueoussolution of polyvinyl alcohol (degree of polymerization: 2,000) on thelight-sensitive layer of the light-sensitive material (C) prepared inComparison Example 2 and drying the material to obtain a protectivelayer having a dry thickness of 50 μm.

Evaluation of light-sensitive material

The light-sensitive material (E) was imagewise exposed to light througha green filter which transmits a light having a wavelength from 500 to600 nm and in which the density continuously changed, using a tungstenlamp at 2,000 lux for 1 second and then heated on a hot plate at 125° C.for 20 seconds. In these process, the light-sensitive material waseasily handled, because the protective layer was provided on thelight-sensitive layer. After the protective layer was removed, theexposed and heated light-sensitive material was then combined with theimage-receiving material and passed through press rolls under pressureof 350 kg/cm² to obtain a clear magenta positive image on the imagereceiving element. The density of the obtained image was measured usingMacbeth reflection densitometer. Each of the maximum density and theminimum density was the same as in Comparison Example 2. However, therelative sensitivity of the obtained image increased to 350.

COMPARISON EXAMPLE 3 Preparation of solution of color developer

To 125 g of water was added 11 g of 40% aqueous solution of sodiumhexametaphosphate, and were further added 34 g of zinc3,5-di-α-methylbenzylsalicylate and 82 g of 55% slurry of calciumcarbonate, followed by coarsely dispersing in a mixer. The coarsedispersion was then finely dispersed in Dynomill dispersing device. To200 g of the resulting dispersion were added 6 g of 50% latex of SBR(styrene-butadiene rubber) and 55 g of 8% aqueous solution of polyvinylalcohol, and the resulting mixture was made uniform to prepare asolution of a color developer.

Preparation of light-sensitive material

To a mixture of 5.0 g of the light-sensitive microcapsule dispersionprepared in Comparison Example 2 and 5.0 g of the solution of a colordeveloper were added 1.0 g of 1% aqueous solution of the anionicsurfactant used in Comparison Example 1 and 1.0 g of 10% solution(solvent: water/ethanol=50/50 as volume ratio) of guanidinetrichroloacetate to prepare a coating solution.

The coating solution was uniformly coated on a polyethyleneterephthalate film (thickness: 100 μm) using a coating rod of #40 togive a layer having a wet thickness of 70 μm and dried at about 40° C.to obtain a light-sensitive material (F).

Evaluation of light-sensitive material

The light-sensitive material (F) was imagewise exposed to light using atungsten lamp at 2,000 lux for 1 second and then heated on a hot plateat 125° C. for 40 seconds. The exposed and heated light-sensitivematerial was then passed through press rolls under pressure of 350kg/cm² to obtain a magenta positive image on the light-sensitivematerial. The density of the obtained image was measured using Macbethreflection densitometer. Each of the maximum density and the minimumdensity respectively was 0.70 and 0.25. Further, the sensitivity of theobtained image was supposed to have a relative value of 100 to determinethe relative sensitivity.

EXAMPLE 4 Preparation of light-sensitive material

The light-sensitive material (G) was prepared by coating 3% aqueoussolution of polyvinyl alcohol (degree of polymerization: 2,000) on thelight-sensitive layer of the light-sensitive material (F) prepared inComparison Example 3 and drying the material to obtain a protectivelayer having a dry thickness of 10 μm.

Evaluation of light-sensitive material

The light-sensitive material (G) was evaluated in the same manner as inComparison Example 3. Each of the maximum density and the minimumdensity was the same as in Comparison Example 3. However, the relativesensitivity of the obtained image increased to 300.

Further, the same result was obtained in the light-sensitive materialhaving a thicker protective layer than the above layer. It is apparentfrom the results that a clear image can be formed on the light-sensitivematerial having a protective layer with high sensitivity and withoutdisturbing the image formation.

I claim:
 1. A light-sensitive material comprising a support and alight-sensitive layer containing silver halide, a reducing agent, anethylenically unsaturated polymerizable compound, said silver halide andsaid ethylenically unsaturated compound being contained in microcapsuleswhich are dispersed in the light-sensitive layer, and said ethylenicunsaturated compound being contained in microcapsules in an amount of 5to 1.2×10⁵ times by weight as much as the amount of the silverhalide,wherein the light-sensitive layer is provided thereon with acover sheet.
 2. The light-sensitive material as claimed in claim 1,wherein the cover sheet is a transparent sheet.
 3. The light-sensitivematerial as claimed in claim 1, wherein the cover sheet is anoxygen-impermeable sheet.
 4. The light-sensitive material as claimed inclaim 1, wherein the cover sheet has thickness of from 1 μm to 1 mm. 5.The light-sensitive material as claimed in claim 1, wherein thelight-sensitive layer further contains a color image forming substance.6. The light-sensitive material as claimed in claim 1, wherein thelight-sensitive layer further contains a color image forming substance,said color image forming substance being contained in the microcapsules.7. The light-sensitive material as claimed in claim 1, wherein thelight-sensitive layer further contains a color image forming substance,said color image forming substance comprising a color former and a colordeveloper, one of said color former and color developer being containedin the microcapsules, and the other being arranged outside of themicrocapsules.
 8. The light-sensitive material as claimed in claim 1,wherein the light-sensitive layer further contains a color image formingsubstance, said color image forming substance comprising a color formerand a color developer, said color former being contained in themicrocapsules, and said color developer being arranged outside of themicrocapsules.
 9. The light-sensitive material as claimed in claim 1,wherein the reducing agent is contained in the microcapsules.
 10. Alight-sensitive material comprising a support and a light-sensitivelayer containing silver halide, a reducing agent, an ethylenicallyunsaturated polymerizable compound, said silver halide and saidethylenically unsaturated compound being contained in microcapsuleswhich are dispersed in the light-sensitive layer, and said ethylenicunsaturated compound being contained in microcapsules in an amount of 5to 1.2×10⁵ times by weight as much as the amount of the silverhalide,wherein the light-sensitive layer is provided thereon with aprotective layer.
 11. The light-sensitive material as claimed in claim10, wherein the protective layer contains a polymer having atransmission coefficient of oxygen of not more than 1.0×10⁻¹¹ cm³·cm/cm² ·sec.cmHg.
 12. The light-sensitive material as claimed in claim10, wherein the protective layer is a porous layer.
 13. Thelight-sensitive material as claimed in claim 10, wherein the cover sheethas a thickness of from 0.1 μm to 50 μm.
 14. The light-sensitivematerial as claimed in claim 10, wherein the light-sensitive layerfurther contains a color image forming substance.
 15. Thelight-sensitive material as claimed in claim 10, wherein thelight-sensitive layer further contains a color image forming substance,said color image forming substance being contained in the microcapsules.16. The light-sensitive material as claimed in claim 10, wherein thelight-sensitive layer further contains a color image forming substance,said color image forming substance comprising a color former and a colordeveloper, one of said color former and color developer being containedin the microcapsules, and the other being arranged outside of themicrocapsules.
 17. The light-sensitive material as claimed in claim 10,wherein the light-sensitive layer further contains a color image formingsubstance, said color image forming substance comprising a color formerand a color developer, said color former being contained in themicrocapsules, and said color developer being arranged outside of themicrocapsules.
 18. The light-sensitive material as claimed in claim 10,wherein the reducing agent is contained in the microcapsules.